I'm not sure who Ariel is in this context without more information. It could be a unique character created specifically for this 'never - ending story' that has its own set of characteristics and a role within the plot.
Ariel could be any character created by the fanfic author. It might be a mermaid, as the name Ariel is often associated with mermaids in popular culture.
Ariel is mostly not a real story. It could be from a fantasy world, a product of someone's creativity. There's no historical or factual basis for it to be considered real.
One idea could be that Annie and Riley start a business together in the 90210 setting. They might face challenges like getting investors and dealing with competition, but their friendship helps them through.
There could be a kind-hearted truck driver who gives Riley a ride on part of the journey to Minnesota. This character could offer some words of wisdom to Riley during the trip.
She could be more assertive in a rather dark way. Ursula is a very dominant character. Ariel, growing up under her influence, might not be as gentle as in the original story. For example, when it comes to getting what she wants, she might use more forceful or underhanded methods, rather than her pure - hearted charm in the original.
Often, there are themes related to family and future. For example, how Ariel and Eric plan for their baby's future, what kind of world they want to bring the child into. There could also be a theme of protection. Since Ariel has had her fair share of enemies in the original story, she might be extra cautious about protecting her unborn child from any potential threats.